Accupro T1620163 Spiral Point Tap 4-40 3 Flute Hss

Product Description

The ACCUPRO T1620163 is a spiral point plug tap designed for threading 4-40 unified coarse holes in metalworking applications. Built from 3% vanadium high speed steel with an oxide finish, it delivers improved wear resistance and lubricity compared to standard HSS taps. The plug chamfer distributes cutting load across the first several threads, making it well suited for through-hole tapping operations. With 3 flutes and a spiral point geometry, chips are pushed forward ahead of the cutting edge to keep the flutes clear during the cut. Overall length is 1.87 inches with an 11 mm thread length and an H3 thread limit for controlled fit tolerance.

This tap is rated for use in stainless steel, which demands a tougher, more wear-resistant tool material. The 4-40 thread size is common in precision fastening applications including instrument enclosures, electronics chassis, small fixtures, and light mechanical assemblies. Machinists and tool-and-die workers will find this tap appropriate for both manual and low-speed machine tapping setups where chip management in a through-hole is the priority. Right-hand thread direction matches standard 4-40 fastener orientation.

Key Features

• Spiral point geometry pushes chips forward, keeping flutes clear in through-hole applications
• 3% vanadium high speed steel construction for improved toughness and wear resistance in stainless steel
• Oxide finish reduces friction and provides light corrosion resistance during storage and use
• H3 thread limit ensures controlled tolerance for standard 4-40 fit classes
• Plug chamfer distributes cutting forces gradually for smoother thread entry
• Right-hand thread direction, no coolant-through required

Compatibility

Designed for tapping 4-40 unified coarse right-hand threads in through-hole configurations, with rated material application in stainless steel. Suitable for use in manual tap handles and low-speed machine tapping operations accepting a 3.58 mm shank diameter.

Installation Notes

This tap should be installed and operated by a qualified machinist familiar with thread cutting practices. Ensure the workpiece is securely clamped and properly aligned before beginning the tapping cycle. Use appropriate cutting fluid or tapping compound rated for stainless steel to extend tool life and improve thread finish. Do not exceed recommended spindle speeds for the material and tap size, and back off periodically to break chips if tapping manually.